Applications of particle physics to the early universe

Abstract

In this thesis, I show some of the results of my research work in the field at the crossing between Cosmology and Particle Physics. The Cosmology of several models of the Physics Beyond the Standard Model is studied. These range from an inflationary model based on the condensation of a ghost-like scalar field, to several models motivated by the possibility that our theory is described by a landscape of vacua, as probably implied by String Theory, which have influence on the theory of Baryogenesis, of Dark Matter, and of Big Bang Nucleosynthesis. The analysis of the data of the experiment WMAP on the CMB for the search of a non-Gaussian signal is also presented and it results in an upper limit on the amount on non-Gaussianities which is at present the most precise and extended available.